1. Technical Field
The present disclosure relates to lens actuators, and particularly, to a voice coil motor for driving a lens barrel.
2. Description of Related Art
A voice coil motor is preferred for driving lenses in image capturing devices to achieve an auto-focus function of the image capturing device. A typical voice coil motor includes a moveable frame for accommodating a lens barrel with lenses therein, a coil wrapped around the moveable frame, a number of magnets, a stationary frame for fixing the magnets and accommodating the moveable frame, and a resilient plate interconnecting the stationary frame and the moveable frame. The resilient plate is configured for holding the moveable frame on the stationary frame.
When a current is applied to the coil, a magnetic force is produced between the magnets and the coil, and the moveable frame with the lens barrel moves upward relative to the stationary frame. When the current is cut off, the moveable frame with the lens barrel is reset to its original position under a resilient force applied by the resilient plate. However, during the movement of the moveable frame, the magnetic force must overcome the resilient force. This causes a large current and wastes electricity.
Therefore, it is desirable to provide a voice coil motor, which can overcome or at least alleviate the above-mentioned problems.